Arcing means for brush holders



Feb. 26, 1924. 1,485,127

E. SEARS meme MEANS FOR BRUSH nowmns Filed Sent. 13 1922 r I 58 I is! I 07/ 2 G Patented Feb. 26, 1924.

UNITED STATES EDWARD SEARS, OF DEER- LODGE, MONTANA.

ARGING MEANS FOR BRUSH HOLDERS.

Application filed September 13, 1922. Serial No. 587,959.

To all whom it may concern:

Be it known that I, EDWARD SEARS, a citizen of the United States, and a resident of Deer Lodge, in the county of Powell and State of Montana, have invented certain new and useful Improvements in Arcing Means for Brush Holders, of which the following is a description, reference being had to the accompanying drawing, which forms a part of my specification. V

My invention relates to means adapted to brush holders used in connection with electrical generators and motors; that is to say to means adapted for use with brush holders employed in connection with all types of commutating motors and generators; and the invention has for its object the provision of a construction whereby the air gap between the brush holders and the case of the motor or generator will be such that in the event of flashing or arcing at the points where the brushes are in contact with the commutator, the flash or are will be conducted from the brush holder to the motor or generator case across a comparatively small gap and also at a distance or point considerably removed from the string band or winding at the end of the armature, namely the band which is usually disposed between the copper bars and the end bell of the armature.

The purpose of my invention is to provide a brush holder of such construction or provided with means whereby any resultant arcs will be conducted away from the insulators whereby the brush holders are usually maintained in place; the are on the other hand being conveyed or conducted to the motor or generator case so that no damage.

will be done to the brush holder insulators or the string band of the armature; which, however, would be the case, where unbalanced conditions induce undue disturbance on the commutator, if my improved means is not employed.

The objects and advantages of my invention will be more readily comprehended from the detailed description of the accompanying drawing, wherein Figure 1 is an end elevation, more or less diagrammatic, of the commutator end of an armature and a portion of the housing or casing.

Figure 2 is an end elevation of the commutator end of the armature with a number of brush holders provided with my improved means and with the casing removed.

Figure 3 is a detail view, in elevation, of my improved brush holder.

Figure 4c is a side elevation thereof.

Figure 5 is a bottom plan view thereof.

In order to illustrate my invention, I have shown it applied to a style of brush holder in use on a well known type of traction motor; it being understood, however, that the invention is applicable to and that its specific construction may vary with the different types of brush holders employed.

As the general construction of the armature; the commutator and correlated parts, as well as the general application of the brush holders to the commutator, form no part of my invention, a detailed description of said elements and their correlation need not be entered into beyond a general reference to the elements disclosed in the drawings for the purpose of comprehending my invention which contemplates providing the respective brush holders shown at 10; with an extension or horn indicated at 11 whereby the air gap between the brush holders and the motor or generator case indicated at 12 is materially reduced so that any undue disturbance on the commutator, indicated at 13, of the armature 14, will allow the arc resulting at the respective brushes, to quickly jump or be conveyed through the motor or generator case to ground and thus afiord protection for the adjacent portions of the armature and the insulators of the respective brush holders.

The extension, which may consist of an integral part or a separate portion secured to the brush-holding end of the holders, is preferably disposed in the angular or inclining manner more clearly shown in Figures 1 and 3 in order that a considerable distance or space may be provided between the string band, indicated at 15, of the armature and the end bell thereof, with the result that any flash or are occurring at the respective brush-holders will be conveyed a com paratively great distance away from said portions of the armature and into proximity with the motor-casing whereby it will be grounded through the motor or generator case 12 because of the comparatively small air gap intermediate of the arcing horn or extension 11 and the motor or generator case.

As previously stated, by providing the brush holders with my improved arcing horn, any arcing that may transpire to the commutation will be quickly suppressed or caused to ground and result in the opening of the overload release or circuit breakers arranged in the motor circuits and thus prevent the frequent heavy damage to the armature or porcelain insulators of the brush holders that has heretofore been encountered.

In motors employing brush holders as heretofore constructed, that is to say brush holders without my improved means, any flash-over that might occur would take place in close proximity to the band on the end of the commutator because of its nearness to the armature head. As a result of this condition, the band of the armature is frequently destroyed and the armature grounded; whereas with my improved arcing horn or brush holder provided with my improved means, the are or flash-over will be quickly carried up through the horn and, by reason of its close proximity to the motor or generator case, will ground quickly; the overload-relay or circuit breakers being immediately tripped out and the motor thereby protected.

As previously stated, the construction disclosed in the drawing is merely employed as an exemplification of my invention; it being understood that my new arcing horn is applicable to all commutating motors and generators; the invention, broadly stated, consisting in conducting means disposed intermediate of the brush holders and the case of the motor or generator, either integral with or secured to the holders, and so arranged and disposed that a comparatively small air gap is provided relative to the motor or generator case in order that any are resulting at the respective brush holders will be quickly grounded through the motor or generator case, thereby eliminating the serious difiiculties that have heretofore been encountered by reason of the are maintaining for a sufiicient period, due to the large air gap between the brush holders and the motor ease,--and frequently causing great damage by either destroying the string band of the armature or burning out the mica cone under the string band and causing a complete failure of the armature.

I have shown a simple exemplification of the invention, which has been described in terms empl yed merely as terms of description and not as terms of limitation, structural modifications are possible and may be made without, however, departing from the spirit of my invention.

lVhat I claim is 1. In combination with the brush holders of a commutating motor or generator, conducting means disposed from the brush holder end of the brush holders to a point in proximity to the case of the motor or generator.

2. In combination with the brush holders of a motor or generator, conducting means secured to the brush holding end of the brush holders and disposed in an inclining manner away from the axis of the armature and into proximity with the shell of the motor or generator.

3. Means of the character described, comprising a brush holder, provided with an outwardly extending projection or horn adapted to be disposed in proximity to the case of the motor or generator.

4. Means of the character described, com-- prising a brush holder provided with a projection or horn disposed in a directior away from the axis of the armatur 5. In combination with the case of a commutating motor or generator and its brush holders, conducting means disposed intermediate of the brush holding ends 01' the brush holders and the case of the motor or generator adapted to reduce the air gap therebetween and to induce grounding of an are at the brush holders through the casing EDWARD SEAR-S lVitnesses:

B. FARENWALD, HILDAH SIKLA. 

